Controlling electrode current density of an electrolytic cell

Abstract

Apparatuses and methods for controlling electrode current density of an electrolytic cell during the electrolytic production of a metal, such as aluminum or aluminium, are disclosed. The cell has anodes and cathode plates vertically aligned and arranged in alternating rows. Each electrode defines a connecting region for connecting the electrode to the cell, a middle region, and an ACO (Anode-Cathode Overlap) region extending from the middle region for overlapping adjacent electrodes(s). The ratio of the ACO region's surface area to the middle region's surface area is superior to one. Alternatively, an average cross-sectional ACO region to the middle and connecting regions, is superior than one, preferably superior than 2. The present technology allows maximizing current density in the ACO region. Increasing these ratios has less impact on the environment by reducing heat generation and energy consumption, making the metal production eco-friendly, in particular when used with inert or oxygen-evolving electrodes.

1 . An electrode plate for the electrolytic production of a metal using an electrolytic cell comprising a plurality of said electrodes plates defining anode and cathode plates vertically aligned and arranged in alternating rows of said anode and cathode plates, the electrode plate defining:
 a connecting region adjacent a first end of the electrode plate for connecting the electrode plate to the electrolytic cell;   a middle region extending from the connecting region without overlapping adjacent electrode plates; and   an anode-cathode overlapping (ACO) region extending from the middle region to a second end of the electrode plate opposite to the first end, and configured for overlapping adjacent electrode plate(s);   wherein the electrode plate comprises two opposite surfaces for facing surfaces of electrode plates of adjacent rows; and   wherein a ratio of the ACO region's surface area to the middle region's surface area is superior to one in order to maximize current density in the ACO region.   
     
     
         2 . The electrode plate of  claim 1 , wherein the ACO/middle surface ratio is equal or superior to 2. 
     
     
         3 . The electrode plate of  claim 1 , wherein the electrode plate has a rectangular shape, wherein a width of the electrode plate is constant from the ACO region to the middle and connecting regions. 
     
     
         4 . The electrode plate of  claim 1 , wherein the electrode plate has a goal post shape wherein the middle and connecting regions define a pair of legs on either side thereof, with a central gap between the legs below the ACO region. 
     
     
         5 . The electrode plate of  claim 1 , wherein the electrode plate has a paddle shape, wherein the ACO region has a first width, the middle and connecting regions have a second width, the second width being inferior to the first width. 
     
     
         6 . The electrode plate of  claim 1 , wherein the electrode plate has a trapezoid shape wherein a width of the electrode plate constantly decreases from the second end to the first end of the electrode plate. 
     
     
         7 . The electrode plate of  claim 1 , wherein the ACO region and the middle region of the electrode plate has a trapezoid shape with a width of the electrode plate constantly decreases from the second end of the electrode plate to a junction between the middle and connecting regions, the connecting region having a rectangular shape. 
     
     
         8 . The electrode plate of  claim 1 , wherein a surrounding edge of the surfaces has round transitions between the first end of the plate and the connecting region, and/or the surrounding edge has round transitions between the second end the ACO region. 
     
     
         9 . The electrode plate of  claim 1 , wherein the metal to produce is aluminum, the electrode plate being wettable by liquid aluminum metal. 
     
     
         10 . The electrode plate of  claim 1 , wherein the electrode plate is a cathode plate. 
     
     
         11 . An electrode plate for the electrolytic production of a metal using an electrolysis cell comprising a plurality of said electrodes plates defining anode and cathode plates vertically aligned and arranged in alternating rows of said anode and cathode plates, the electrode plate defining:
 a connecting region adjacent a first end of the electrode plate for connecting the electrode plate to the electrolytic cell;   a middle region extending from the connecting region without overlapping adjacent electrode(s); and   an ACO region extending from the middle region and configured for overlapping adjacent electrodes(s);   wherein an average cross-sectional area ratio of the ACO region to the middle and connecting regions is superior to one in order to maximize current density in the ACO region while retaining a mechanical strength of the connecting region for supporting the electrode plate.   
     
     
         12 . The electrode plate of  claim 11 , wherein the average ACO/middle cross-sectional area ratio is equal or superior to 2. 
     
     
         13 . The electrode plate of  claim 11 , wherein the electrode plate has a goal post shape wherein the middle and connecting regions define a pair of legs on either side thereof, with a central gap between the legs below the ACO region. 
     
     
         14 . The electrode plate of  claim 11 , wherein the electrode plate has a paddle shape, wherein the ACO region has a first width, the middle and connecting regions have a second width, the second width being inferior to the first width. 
     
     
         15 . The electrode plate of  claim 11 , wherein the electrode plate has a trapezoid shape wherein a width of the electrode plate constantly decreases from the second end to the first end of the electrode plate. 
     
     
         16 . The electrode plate of  claim 11 , wherein the ACO region and the middle region of the electrode plate has a trapezoid shape with a width of the electrode plate constantly decreasing from the second end of the electrode plate to a junction between the middle and connecting regions, the connecting region having a rectangular shape. 
     
     
         17 . The electrode plate of  claim 11 , wherein the electrode plate comprises two opposite surfaces for facing surfaces of electrode plates of adjacent rows, and wherein a surrounding edge of the surfaces has round transitions between the first end of the plate and the connecting region, and/or the surrounding edge has round transitions between the second end the ACO region. 
     
     
         18 . The electrode plate of  claim 11 , wherein the metal is aluminum, the electrode plate being wettable by liquid aluminum metal. 
     
     
         19 . The electrode plate of  claim 11 , wherein the electrode plate is a cathode plate. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . A method for controlling the current density of a plurality of electrodes plates defining anode and cathode plates vertically aligned and arranged in alternating rows in an electrolytic cell, the electrode plate defining:
 a connecting region for connecting the electrode plate to the electrolytic cell;   an middle region extending from the connecting region without overlapping adjacent electrode(s); and   an ACO region extending from the middle region and configured for overlapping adjacent electrodes(s);   the method comprising the step of:   providing electrode plates in which an average cross-sectional area ratio of the ACO region to the middle and connecting regions is superior to one in order to maximize current density in the ACO region while retaining a mechanical strength of the connecting region for supporting the electrode plate.   
     
     
         25 . (canceled)